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2.3 Surge Protection Devices (SPDs)
for PV installation
Over-voltage protection with surge arresters should be provided when the PV
power system is installed. The grid connected inverter is not fitted with SPDs in both PV input
side and mains side.
Induced surges are the most likely cause of lightning damage in majority or installations,
especially in rural areas where electricity is usually provided by long overhead lines. Surges
may affect both the PV array conduction and the AC cables leading to the building.
Specialists in lightning protection should be consulted during the end use application. Using
appropriate external lightning protection, the effect of a direct lightning strike into a building
can be mitigated in a controlled way, and the lightning current can be discharged into the
ground.
To protect the AC system, surge suppression devices (SPD type2) should be fitted at the main
incoming point of AC supply (at the consumer's cutout), located between the inverter and
the meter/distribution system; SPD (test impulse D1) for signal line according to EN 61632-1.
All DC cables should be installed to provide as short a run as possible, and positive and
negative cables of the string or main DC supply should be bundled together.
Avoiding the creation of loops in the system. This requirement for short runs and bundling
includes any associated earth bundling conductors. Spark gap devices are not suitable to be
used in DC circuits once conducting; they won't stop conducting until the voltage across their
terminals is typically below 30 volts.
WARNING
Lightning will cause damage either from a direct strike or from surges due to a nearby strike.
Installation of SPDs to protect the inverter against mechanical damage and excessive
stress include a surge arrester in case of a building with external lightning protection
system (LPS) when separation distance is kept. To protect the DC system, surge suppression
device (SPD type2) should be fitted at the inverter end of the DC cabling and at the array
located between the inverter and the PV generator, if the voltage protection level (VP) of the
surge arresters is greater than 1100V, an additional SPD type 3 is required for surge
protection for electrical devices.
Machine Translated by Google
